Valve arrangement

ABSTRACT

The valve arrangement comprises a predetermined number of individual valve functionalities, arranged in a manner parallel to each other. A fixed connector plate ( 3 ) has a number of sample funnel tubes ( 6 ) and output connections ( 8 ) for forward transfer of the samples arranged offset from the above. A valve plate ( 14 ) with the same number of sample loops ( 24 ) for accommodating precisely measured sample amounts may be displaced linearly with respect to the connector plate. In a first position the sample loops are connected to the sample funnel tubes and in a second position with the output connections.

[0001] The invention relates to a valve arrangement with severalindividual valve functions arranged parallel to one another.

[0002] The majority of valve arrangements conventionally used inanalysis at the present time have a number of disadvantages that have anadverse effect on the throughput rate in particular, but also on theprecision of the measurement or analysis results obtainable. A furtherdisadvantage is that known valve arrangements are of very complicatedconstruction and therefore susceptible to failure.

[0003] The object of the invention is to provide a valve arrangementwhich does not exhibit said disadvantages.

[0004] According to the invention, this is achieved by means of a valvearrangement characterized by the features indicated in claim 1. Apreferred embodiment of the invention is described below with the aid ofthe accompanying drawings, in which:

[0005]FIG. 1 is a perspective view of a valve arrangement according tothe invention;

[0006]FIG. 2 is a top view of the valve arrangement of FIG. 1 in oneposition of the valve plate;

[0007]FIG. 3 shows a longitudinal section along A-A in FIG. 2;

[0008]FIG. 4 shows a longitudinal section along B-B in FIG. 2;

[0009]FIG. 5 shows a cross-section along C-C in FIG. 2;

[0010]FIG. 6 shows a cross-section along D-D in FIG. 2;

[0011]FIG. 7 shows a cross-section along E-E in FIG. 2;

[0012]FIG. 8 is another top view of the valve arrangement in the secondposition of the valve plate;

[0013] FIGS. 9-11 show the sections A-A, C-C and D-D in the secondposition; and

[0014]FIGS. 12a and 12 b show a flow diagram of one possible use of thevalve arrangement together with a selector valve.

[0015] The valve arrangement shown in FIG. 1 is an eight-way valve andconsists of a support 1 in the form of a block or plate, to which theother parts of the valve arrangement are fixed and which in turn isfixed in an analytical instrument or the like. The support is made ofaluminium. Attached to one side of the support 1 is a step motor 2 fordriving or switching the valve. Firmly attached to the opposite side ofthe support 1 is a horizontal plate 3 on which the essential input andoutput connections of the valve arrangement are located and which istherefore referred to hereafter as the connector plate. The connectorplate is made of a chemically inert material, e.g. chrome steel.

[0016] On one side of the surface of the connector plate 3, in aplatform 4 that projects upwards, there is a trough 5 in which eightsample funnel tubes 6 for sample injection are arranged at the samedistance from one another. The distance between the funnels 6 isidentical to the well spacing of microtitre plates so that the eightcannulas of an eight-way pipette or syringe can simultaneously injectthe samples taken from one row of a microtitre plate into the eightsample funnel tubes. The sample funnel tubes are located in the upperpart of drilled holes which lead through the connector plate to its flatunderside.

[0017] An attachment 7, whose function is illustrated in greater detailbelow, is provided on the platform 4 for raising the side walls of thetrough.

[0018] On the other side of the surface of the connector plate 3 a rowof eight output connections 8 is arranged, parallel to the row of samplefunnel tubes 6, in eight drilled holes leading through the plate to itsunderside. The connections 8 are designed as high-pressure connectionsand are used for coupling to lines which, depending on the use of thevalve arrangement, lead individually to a number of detectors or via aselector valve to one detector, for example a mass spectrometer, asexplained in greater detail below.

[0019] The row of output connections 8 is offset in the longitudinaldirection relative to the row of sample funnel tubes 6 by a distancewhich is less than the well spacing of microtitre plates. The offset is2 mm in the present case. This distance corresponds to the valve lift,as shown below.

[0020] Located on the front side of the connector plate 3 are a furtherconnection 9 and two drilled holes 11, 12. The connection 9 sits in themouth part of a drilled hole 10 running longitudinally through theconnector plate 3 (cf. FIGS. 5-7), which hole 10 combines withtransverse drilled holes to form an overflow system and can be coupledvia the connection 9 to a waste receptacle.

[0021] The upper drilled hole 11 leads from inside the trough 5 to theoutside and also serves as a connection to an overflow system forflushing liquid from the trough into a waste receptacle. As explained ingreater detail below, a larger amount of flushing liquid accumulates inthe trough, so a line of larger dimensions has to be connected to thehole 11.

[0022] The drilled hole 12 runs inside the connector plate over theentire length and, as shown below, combines with a number of transversedrilled holes to form a solvent pressure line, i.e. a feed system forsolvent which is normally fed by a high-pressure pump, depending on theapplication. On the far side face of the connector plate 3 in FIG. 1,there is another connection 13 which, with two further connections,forms part of said feed system for the solvent conveyed under pressure.

[0023] The top view of FIG. 2 shows the offset of the sample funneltubes 6 and the output connections 8. The three connections 13 formingpart of the solvent pressure line 12 are also shown.

[0024] Other connecting channels running inside the connector plate 3are shown in the various sectional drawings of FIGS. 4-7 and areexplained in the description below. Arranged underneath the connectorplate 3 is a valve plate 14 in the form of a slide or carriage, which ismoved to and fro between two positions in the longitudinal direction,relative to the connector plate 3, by the step motor 2.

[0025] Underneath the valve plate there is a bearing plate 16 firmlyjoined to the connector plate 3. FIG. 3 shows how the bearing plate 16is fixed to the connector plate 3 by means of screws 18. Arrangedbetween the bearing plate 16 and the valve plate 14 is a ball bearingconsisting of balls 19 housed in two upper parallel grooves 20 runningover the entire length of the underside of the valve plate 14, andcorresponding lower grooves 21, in the surface of the bearing plate 16.

[0026] On its underside the valve plate is provided with two rows 22, 23of eight high-pressure connections which sit in the lower part ofdrilled holes running right through the valve plate to its surface. Oneof the two rows of connections 22 lies in a plane with the funnel tubes6 and the other row of connections 23 lies in a plane with the outputconnections 8. The individual connections within the two rows are thesame distance apart as the sample funnel tubes or the outputconnections, i.e. the distance between the sample receptacles, or thewell spacing, of the microtitre plate. In contrast to those in theconnector plate 3, the two rows of connections 22, 23 in the valve plateare not offset relative to one another in the longitudinal direction.

[0027] The pairs of opposite connections in the two rows are coupledtogether by arc-shaped lines of exactly equal length running underneaththe bearing plate, which constitute sample loops 24. The sample loops 24accommodate precisely measured amounts of sample, which are conveyed toa detector.

[0028] Located on the front side of the valve plate 14 is ahigh-pressure connection 25 which sits in the mouth of a drilled hole 26running almost the entire length of the valve plate. The hole 26 (cf.FIGS. 5-7) combines with transverse drilled holes to form a flushingline, i.e. a system for conveying flushing liquid to the funnel tubes inone of the two valve positions, as illustrated in greater detail below.

[0029] Located in the upper face of the valve plate, in the region ofthe mouths of the drilled holes belonging to the rows of connections 22,23, are sealing strips 27 arranged in two parallel slots, which, bymeans of the pressure with which the valve plate acts against theconnector plate 3 via the screws joining the bearing plate 16 to saidconnector plate 3, reliably isolate the individual channels from oneanother.

[0030] The two positions which the valve plate can adopt correspond tosaid longitudinal offset between the sample funnel tubes 6 and theoutput connections 8. This offset is 2 mm in the present embodiment.Thus the two rows of connections 22, 23 in the valve plate can bebrought in line with, i.e. coupled to, either the sample funnel tubes 6or the output connections 8. This is illustrated in greater detail belowwith the aid of the sectional drawings of FIGS. 4-7.

[0031] In the position of the valve plate 14 shown in longitudinalsection in FIG. 4, the sample funnel tubes 6 are coupled to the row ofconnections 22 of the sample loops 24. At the same time the mouths ofthe flushing line 26 at the contact face between the connector plate andthe valve plate are closed. This can also be seen in the cross-sectionsof FIGS. 5-8, which additionally show the situation on the other side,i.e. with the output connections and the row of connections 23. Thesection C-C of FIG. 5 runs through the median plane of the firsttransverse drilled hole of the solvent pressure line, which is coaxialwith one of the external connections 13. The channel leading to thecontact face is closed in this position. Located on the other side inthis cutting plane is the axis of the first output connection 8, whosemouth on the underside of the connector plate is likewise closed.

[0032] The section D-D of FIG. 6 runs through the axis of the secondsample funnel tube and shows that this funnel is coupled to thecorresponding connection of the row 22 in the valve plate. On the otherside of the loop, the corresponding connection of the row 23 is coupledto the overflow system. Thus, in this position, a sample can be injectedinto the sample funnel tube, thereby filling the sample loop. Excesssample passes into the overflow system. As all eight sample funnel tubes6 are similarly coupled to the sample loops in this position, all eightsample loops can be filled simultaneously.

[0033] Finally, the section E-E of FIG. 7 shows that, in this position,the flushing system at the contact face between the connector plate 3and the valve plate 14 is also closed.

[0034] The situation in the second position of the valve plate is shownin FIGS. 8-11. It can be seen in the top view of FIG. 8 that the outputconnections 8 now coincide with the row of connections 23, while thesample funnel tubes 6 do not coincide with the row of connections 22.This can be seen in the longitudinal section A-A of FIG. 9. The row ofconnections 22 are now coupled to the pressure line 12. Thecross-section C-C running through the first transverse drill hole in thepressure line (cf. FIG. 5) shows in FIG. 10 that the first sample loopis coupled to the pressure system and on the other side to the outputconnection. Thus, in this position, the output connection 8 is coupledto a detector.

[0035] At the same time, as can be seen in the section D-D of FIG. 11,the sample funnel tubes 6 are coupled to the flushing system. Thesolvent fed through the flushing system flushes the sample funnel tube.The cannulas are also flushed at the same time and it is for thispurpose that they remain in the filling position until the flushingprocess has ended. The flushing process is terminated before thesampling sequence so that the eight-way syringe can be refilled andbrought into the injection position. As soon as sampling has ended, thevalve plate is switched back to the first position, in which the sampleloops are immediately filled with the next samples.

[0036] One possible use of the valve arrangement is shown in the flowdiagram of FIG. 12a,b. The valve arrangement according to the inventionworks together with a commercially available selector valve. The outputconnections 8 are coupled via individual lines to the individual inputs1-10 of the selector. The output of the selector is coupled to adetector, for example a mass spectrometer. The solvent pump is coupledsimultaneously to the solvent pressure line 12 and to at least oneindividual input of the selector.

[0037] As already described, in the first position of the valvearrangement according to the invention, illustrated in FIG. 12a, thesample funnel tubes 6 are coupled via the sample loops 24 to theoverflow system. In this position eight samples are appliedsimultaneously by means of an eight-way syringe, which is indicated bythe functional description “INJECT”. Excess sample passes via theoverflow system to a receptacle indicated by “WASTE”. The connections ofthe solvent pressure line are closed in this position of the valvearrangement. The connections of the flushing line are likewise closed.On the other hand, there is a connection between the pump and theselector so that pure solvent is fed to the mass spectrometer for makinga blank measurement.

[0038] The second position, shown in FIG. 12b, couples the solventpressure line to the sample loops and their output connections to theselector valve. By continuing to switch to positions 1-10, the selectorvalve can successively bring the individual samples into the sampleloops and deliver them to the mass spectrometer.

[0039] During this procedure, flushing of the sample funnel tubes 6 andthe syringe cannulas is taking place on the input side of the valveaccording to the invention. The sample funnel tubes 6 are coupled to theflushing system indicated by “CLNINJ”. The flushing liquid flows out ofthe trough 5 into the “WASTE”. When the last sample loop has beenevacuated into the mass spectrometer, the input side is ready for thenext sample application, which takes place almost immediately. Thus,after only a very short delay, the selector valve can deliver the nextsample to the mass spectrometer.

[0040] In this way the mass spectrometer receives an uninterruptedsequence of samples with a negligible delay between each block of eight,affording a throughput rate never previously achieved.

1. Valve arrangement with a given number of individual valve functionsarranged parallel to one another, characterized in that it has a fixedconnector plate with the same given number of sample funnel tubes andthe same given number of output connections, offset relative to thesample funnel tubes, for conveying the samples, and a valve plateprovided with the same given number of sample loops for accommodatingprecisely measured amounts of sample, said valve plate being capable oflinear displacement between a first position, in which the sample loopsare coupled to the sample funnel tubes, and a second position, in whichthe sample loops are coupled to the output connections.
 2. Valvearrangement according to claim 1, characterized in that, in the firstposition of the valve plate, the sample loops are coupled on the outputside to an overflow line.
 3. Valve arrangement according to claim 1,characterized in that, in the second position of the valve plate, thesample loops are coupled on the input side to a solvent pressure lineand at the same time the sample funnel tubes are coupled to a flushingsystem.
 4. Sample processing system, characterized in that it comprisesa valve arrangement according to one of claims 1-3 whose outputconnections are individually coupled to the inputs of a selector valve,the output side of which is coupled to a detector.